The primary biological function of hGH includes stimulating growth, cell repair and regeneration. Once the primary growth period of adolescence concludes, the primary function of hGH in adulthood becomes that of cell regeneration and repair, helping regenerate skin, bones, heart, lungs, liver and kidneys to their optimal, youthful cell levels. As is the case with many of our other hormones or their pre-cursors, such as testosterone, estrogen, progesterone, DHEA and melatonin, hGH levels decline with age. Therapeutically, many of these hormones can be replaced to offset some of the effects of aging such as menopausal symptoms in women or erectile dysfunction in men.
The human body, like every other living entity, works on daily, or circadian, as well as monthly and annual rhythms. Daily growth hormone secretion diminishes with age with roughly half the levels at age forty that we had when we were twenty, and about one-third of those youthful levels at age sixty. In some sixty-year olds, the levels are as low as 25% of the hGH levels in a twenty-year old. Symptoms of aging include loss of muscle, increase of fat, decreased physical mobility, decreased energy levels and as a result, diminished socialization, diminished healing ability and an increased risk of cardiovascular disease and decreased life expectancy. Low hGH levels are associated with the aging process and early onset of disease. For example, Rosen and Bengtsson noted an increased death rate from cardiovascular disease in hGH deficient patients. (Rosen, T., Bengtsson, B. A., Lancet 336 (1990): 285-2880)
Until recently human growth hormone (hereinafter alternatively referred to as hGH) was available only in expensive injectable forms, and benefits from the restoration of hGH levels available only to those with the ability to pay. Most recently substances that can trigger the release of human growth hormone from an individual's own anterior pituitary gland have become available. These are generically referred to as secretagogues. Secretagogues have the ability to restore hGH levels, potentially to the levels found in youth. See, e.g., “Grow Young With hGH” by Dr. Ronald Klatz, President of the American Academy of Anti-Aging, published in 1997 by Harper Collins.
HGH-deficient adults have marked reductions in lean body mass, and within months of hGH treatment, gains in lean body mass, skin thickness and muscle mass are observed. (Cuneo RC et al. J Appl Physiol 1991; 70:695-700; Cuneo RC et al. J Appl Physiol 1991; 70:688-694; Rudman D et al. N Engl J Med 1969; 280:1434-1438).
It is well-established that intravenous (IV) administration of some amino acids results in significant hGH secretion. Intravenous infusion of 183 mg of arginine/kg body weight in females increased hGH levels >20-fold and 30 g of arginine elevated serum hGH levels 8.6 fold in males (Merimee T J et al. N Engl J Med 1969; 280:1434-1438; Alba-Roth J et al. J Clin Endocrinol Metab 1988; 67:1186-1189). Other amino acids, such as methionine, phenylalanine, lysine, histidine, and ornithine have also led to marked increases in hGH (Alba-Roth, Muller, Schopohl, & von Werder, 1988; Chromiak & Antonio, 2002; Gourmelen, M., M. Donnadieu, et al. (1972) Ann Endocrinol (Paris) 33(5): 526-528).
Given the difficulties in IV administration of amino acids for widespread use, interest in elucidating the hGH response to oral amino acid supplements prompted testing of such supplements containing mainly arginine, lysine and ornithine at varying amounts. Yet the pronounced variability in results among these studies, which differed in aspects including subject population, supplement composition, and dosage methodologies, make clear the complexities involved in the design of an effective supplement for supporting hGH levels in the general public. (Suminski RR et al. Int J Sport Nutr 1997; 7:48-60; Lambert MI et al. Int J Sport Nutr 1993; 3:298-305; Corpas E et al. J Gerontol 1993; 48:M128-M133; Isidori A et al. Curr Med Res Opin 1981; 7:475-481; Fogelholm GM et al. Int J Sport Nutr 1993; 3:290-297; Chromiak J A, Antonio J. Nutrition 2002 July; 18(7-8):657-61).
Thus determination of an effective and safe oral functional blend that stimulates hGH secretion in the general population is important to determine since athletes, entertainers and now the general public seek effective hGH support supplements and understand hGH to have rejuvenating properties.
Indeed, once partial to athletes and entertainers, the desire for effective supplements to provoke growth hormone (hGH) increases now extends to the general public. Not only do they have a goal of building lean tissue and reducing fat, but also in improving skin quality and other rejuvenating qualities that hGH is understood to provide. Despite proceeding literature on oral amino acids for use in stimulating hGH, evidence for an optimized oral amino acid-containing blend able to stimulate hGH in the general public including both men and women of a wide age range is not clear.
It would be desirable to provide a nutritional supplement for elevating hGH release, in particular an amino acid-containing composition that is well tolerated having the result of increasing or elevating hGH release in those individuals whose hGH release rates have slowed as a function of increasing age or that have normal hGH levels but desire higher hGH levels. Although some existing nutritional supplements claim to impact the production of natural human growth hormone, there is a need for an improved nutritional supplement that efficiently enhances the production and effect of natural human growth hormone in the general population.